Biomass hydrogen production technology is an emerging research field. Biomass contains a large amount of H2 element, so this technology can replace traditional H2 production. The exploitation of H2 from biomass using conventional methods is so far not commercialized, and nanotechnology may provide a viable commercial and environmentally friendly route for this. Here, we first have a critical review on the use of nanotechnology in green bio-H2 production including thermochemical, biological, and electrochemical approaches summarizing the merits and limitations. Then, the current technology and development overview of biomass hydrogen production are summarized. Finally, the important role played by nanostructured materials, mainly in the form of nanocatalysts, in the process of biomass hydrogen production is summarized. Nanocatalysts can improve the efficiency of biomass hydrogen production and provide a guarantee for large-scale biomass hydrogen production and commercial application. Graphical abstract: Reproduced with permission.